With the twin goals of making fuel from algae and reducing emissions of heat-trapping gases, a start-up company co-founded by a Colorado State University professor recently introduced a strain of algae that loves carbon dioxide into a water tank next to a natural gas processing plant. The water is already green-tinged with life.

The Southern Utes, one of the nation's wealthiest American Indian communities thanks to its energy and real-estate investments, is a major investor in the professor's company. It hopes to gain a toehold in what tribal leaders believe could be the next billion-dollar energy boom.

But from the tribe's perspective, the business model here is about more than business."